NGC 7331
NGC 7331 - The Milky Way's Twin?
NGC 7331 is an unbarred spiral galaxy about 40 million light years away in the direction of the constellation Pegasus, the winged horse of ancient Greek mythology. The words "in the direction of" is used here, since no astronomical object is ever really "in" a constellation. Constellations are made up collections of stars by humans that are as fleeting as cloud shapes on an astronomical scale. NGC 7331 appears to be surrounded by a group of galaxies, but all of the other galaxies highlighted in this image are much much further away at 300 and 400 million light years distant. Hovering over the image will show the names of the other brighter galaxies in this image. Until the early 2000s, it was believed that NGC 7331 was very similar to our own Milky Way galaxy and hence called its twin. However, discoveries have proven that our galaxy, although similar in size and number of stars, is actually a barred spiral galaxy that has a bar structure running through the center. NGC 7331 cleary has no bar and is therefore different from our own galaxy. One interesting observation about NGC 7331 is that if you look closely enough you will see that the center core of the galaxy is not perfectly centered, as it favors the left side in this image. Furthermore, it appears slightly inclined compared to the disk of the entire galaxy. Amazing enough, this central disk is actually rotating in the opposite direction of the galaxy, a mystery among many others about the nature of galaxy formation and their behaviors.
Optics: RC Optical System 20" F/8.2 (4165.6 mm Focal Length) Date: June-August 2020
Camera: SBIG STXL-11000 with AO-X Adaptive Optics Location: Columbus, Texas
Exposure: LRGB = 820:80:80:100 minutes Imager: Kent E. Biggs